Expression Plasticity of Peroxisomal Acyl-Coenzyme A Oxidase Genes Implies Their Involvement in Redox Regulation in Scallops Exposed to PST-Producing .

Filter-feeding bivalves can accumulate paralytic shellfish toxins (PST) produced by toxic microalgae, which may induce oxidative stress and lipid peroxidation. Peroxisomal acyl-coenzyme A oxidases (ACOXs) are key enzymes functioning in maintaining redox and lipid homeostasis, but their roles in PST response in bivalves are less understood. Herein, a total of six and six s were identified in the and genome, respectively, and the expansion of s was observed. Gene expression analysis revealed an organ/tissue-specific expression pattern in both scallops, with all s being predominantly expressed in the two most toxic organs, digestive glands and kidneys. The regulation patterns of scallop s after exposure to different PST-producing algaes (ACDH) and (AM-1) were revealed. After ACDH exposure, more differentially expressed genes (DEGs) were identified in . digestive glands (three) and kidneys (five) than that in . (two), but the up-regulated DEGs showed similar expression patterns in both species. In . , three DEGs were found in both digestive glands and kidneys after AM-1 exposure, with two same s being acutely and chronically induced, respectively. Notably, these two s also showed different expression patterns in kidneys between ACDH (acute response) and AM-1 (chronic response) exposure. Moreover, inductive expression of s after AM-1 exposure was observed in gills and mantles, and all DEGs in both tissues were up-regulated and their common DEGs exhibited both acute and chronic induction. These results indicate the involvement of scallop s in PST response, and their plasticity expression patterns between scallop species, among tissues, and between the exposure of different PST analogs.